Free vibration analysis of a laminated beam with delaminations is presented using a layerwise theory. Equations of motion are derived from the Hamilton's principle, and a finite element method is developed to formulate the problem. Numerical results are obtained and compared with those of other theories addressing the effects of the lamination angle, location, size and number of delamination on vibration frequencies of delaminated beams. It is found that a layerwise approach is adequate for vibration analysis of delaminated composites.